JPH0533819A - Drive force transmission device - Google Patents

Abstract

PURPOSE:To improve a torque transmission characteristic in the low differential area and high differential area of a vehicle in a drive force transmission, device provided with a friction clutch to transmit the torque of inner and outer rotary members and a pushing pressure generating means to generate pushing pressure for pushing the friction clutch according to the differential rotation. CONSTITUTION:A rotor 14 constituting a pushing pressure generating means is formed into a disk shape, and a lot of recessed portions 14b having an inclination face 14b are provided at one side face of the rotor 14 in the peripheral direction, and one or a plurality of vanes 14c is also provided on the other side of the rotor 14 so as to be extended in the outer radial direction. By this constitution, torque transmission properties in all differential areas can be improved utilizing the fluid pressure generated in each recessed portion 14b in the low differential area and the fluid pressure generated by vanes 14c in the high differential area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving force transmission device which is interposed between a pair of rotating members which are coaxially supported and which transmits torque between these two members.

[0002]

2. Description of the Related Art Such a driving force transmitting device is interposed between two rotating members which are coaxially supported with each other, and connects the two members so that they can transmit torque when they rotate relative to each other. It is roughly classified into one used as a connecting mechanism for driving the rotating member and one used as a differential limiting mechanism for limiting the rotation difference between these two members.
The former coupling mechanism is mainly installed in one power transmission path of a real-time four-wheel drive vehicle, and the latter differential limiting mechanism is mainly installed in each differential of the vehicle.

However, as a conventional driving force transmitting device, as shown in Japanese Patent Laid-Open No. 63-240429, it is arranged between both inner and outer rotating members that are coaxially and relatively rotatable. A friction clutch that operates by relative rotation of the rotating member to generate a frictional engaging force that connects the two rotating members so that torque can be transmitted, and that increases or decreases the frictional engaging force according to an axial pressing force applied, and both rotations There is a driving force transmission device including a pressing force generating means for generating a pressing force in the axial direction according to relative rotation of a member and applying the pressing force to the friction clutch.

Further, in the driving force transmitting device, the pressing force generating means is assembled between the rotating members so as to be liquid-tightly slidable in the axial direction and integrally rotatable with the outer rotating member so that the friction is generated. An operating piston facing one side of the clutch,
A fluid chamber formed between the outer rotating member and the working piston, in which a viscous fluid is sealed at a predetermined interval in the axial direction,
It is generally constituted by a rotor that is integrally rotatably assembled to the inner rotating member in the same fluid chamber and that generates a fluid pressure in the fluid chamber during rotation.

In this type of driving force transmission device,
When relative rotation occurs between both rotary members, relative rotation occurs between the working piston that is integrally rotatably mounted on the outer rotary member and the rotor that is integrally rotatably mounted on the inner rotary member, and the rotor in the fluid chamber is At, the viscous fluid in the fluid chamber is forced to flow, and fluid pressure is generated in the fluid chamber due to flow resistance and the like. That is, pressure corresponding to the differential rotation speed is generated in the pressing force generating means. This pressure pushes the actuating piston in the axial direction to push the friction clutch, and the friction engagement force that connects both rotating members to the torque transmission is generated in the clutch. The frictional engagement force is proportional to the differential rotation speed, and torque proportional to the differential rotation speed is transmitted between the two rotary members from one to the other. Therefore, the driving force transmission device functions as a connecting mechanism between the driving side rotation member and the driven side rotation member in one power transmission system path of the four-wheel drive vehicle, and also between the driving side and the driven side rotation member and both driving sides. It also functions as a differential limiting mechanism between the rotating members or between both driven side rotating members.

By the way, in the driving force transmission device of the above-mentioned type, when the driving force transmission device is adopted as the driving force transmission device of a four-wheel drive vehicle, the driving force is generated in accordance with the differential rotation of the front and rear wheels. Not only is it transmitted, but it also absorbs the circulating torque peculiar to four-wheel drive and prevents vibrations and rattling noises due to the rotational phase difference between the front and rear wheels during running,
In addition, it is necessary to avoid disturbance during anti-lock braking system (ABS) control. However,
In the above-described driving force transmission device, since the transfer characteristics are substantially the same during forward torque transmission in which the rotation on the drive wheel side increases and during reverse torque transmission in which the rotation on the driven wheel side increases.
The above-mentioned circulation torque cannot be sufficiently absorbed, and ABS cannot be sufficiently dealt with.

In order to deal with this, the applicant of the present invention discloses in Japanese Unexamined Patent Publication No.
As disclosed in Japanese Patent No. 21038, a driving force transmission device is proposed in which torque is sufficiently transmitted to the driven wheel side during positive torque transmission, and torque transmission to the driven wheel side is sufficiently restricted during reverse torque transmission. .. In the driving force transmission device, the pressing force on the friction clutch is different between the forward rotation and the reverse rotation of the rotor by differentiating the shapes of the one side (normal rotation) side and the other (reverse rotation) side of the rotor in the rotation direction. Different from
This causes a difference in the transmission torque at the time of forward and reverse torque transmission. Therefore, although the function is almost satisfactory, it takes time to positionally replace the viscous fluid and the gas when the differential rotation direction is reversed, which may cause a time delay in the pressure response.

As a driving force transmission device for coping with such a problem, the applicant of the present invention has formed the rotor in a disk shape and provided a large number of recesses having inclined surfaces with respect to one rotation direction on the side surface of the rotor in the circumferential direction. Japanese Patent Application No. 2-27
No. 4291 filed. In the driving force transmission device, the wedge action on the fluid of the inclined surface of the recess of the rotor is different due to the difference in the rotation direction of the rotor, and the wedge action is generated or the pressing force is generated when rotating in the direction in which the wedge action is large. The pressing force generated by the means is large, and a large pressing force is applied to the friction clutch. Further, when the rotor rotates in the opposite direction to the above, the wedge action does not occur or the wedge action is small, and the pressing force generated by the pressing force generating means is small, so that the pressing force on the friction clutch is small. Has been done.

For this reason, a great difference occurs in the transmission torque during forward / reverse torque transmission, so that a good function can be exhibited, and the positional replacement of the viscous fluid and the gas when the differential rotation is reversed is in each recess. Since it is performed in such a small area, it is performed instantaneously, and the pressure response becomes good. Further, in the above rotor, when the recesses are formed with inclined surfaces for both the forward and reverse rotation directions, the forward and reverse transmission torques are the same, but there is an advantage that the response in the low differential region is good.

[0010]

In the drive force transmission device, the wedge action on the viscous fluid is generated between the inclined surface of the recess of the rotor and the side wall of the fluid chamber, but pressure is generated in the fluid chamber. When the working piston moves due to this, the gap between the working piston and the rotor increases, so
In the high differential region, the rate of increase of the pressure generated in the fluid chamber with respect to the differential rotation speed is greatly reduced and the transfer torque becomes constant at an early stage, and the torque transmission tends to be insufficient in the high differential region. The broken line graph in FIG. 5 shows the relationship between the differential rotation speed and the transmission torque in the driving force transmission device. Therefore, it is an object of the present invention to address such issues.

[0011]

DISCLOSURE OF THE INVENTION The present invention is arranged between inner and outer rotary members which are coaxially and relatively rotatably positioned, and can be operated by relative rotation of both rotary members to transmit torque to both rotary members. To generate a frictional engagement force coupled to the friction clutch and to increase or decrease the frictional engagement force according to the axial pressing force applied, and to generate an axial pressing force corresponding to the relative rotation of the both rotary members. And a pressing force generating means for applying the same pressing force to the friction clutch. The pressing force generating means can be slid liquidtightly between the rotating members in the axial direction and integrally rotatable with the outer rotating member. An operating piston that is assembled and faces one side of the friction clutch, a fluid chamber that is formed between the outer rotating member and the operating piston, and that contains a viscous fluid at a predetermined interval in the axial direction, and the same fluid. In front of the room In a driving force transmission device that is integrally rotatably assembled to an inner rotating member and configured to generate a fluid pressure in the fluid chamber during rotation, the rotor is formed in a disk shape and is formed on one side surface of the rotor. It is characterized in that a large number of recesses having an inclined surface with respect to at least one rotation direction are provided in the circumferential direction, and one or a plurality of vanes extending radially outward are provided on the other side surface of the rotor.

[0012]

In the driving force transmission device having such a configuration, when differential rotation occurs, the rotor rotates relative to the outer rotating member. In the rotor, a large number of recesses provided on one side surface and vanes provided on the other side surface generate a fluid pressure in the fluid chamber, and the fluid pressure presses the friction clutch via the working piston. As a result, the friction clutch connects both the inner and outer rotating members so that torque can be transmitted, and torque is transmitted between the both rotating members.

In the drive force transmission device, however, both the recesses provided on one side surface of the rotor and the vanes provided on the other side surface of the rotor function to generate a fluid pressure in the fluid chamber, and in particular each recess portion. Contributes to improving the pressure response in the low differential region, and the vanes contribute to improving torque transmission in the high differential region. The relationship between the differential rotation speed and the transmission torque in the driving force transmission device is as shown by the solid line graph in FIG.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a driving force transmission device according to the present invention. As shown in FIG. 4, the driving force transmission device 10 is arranged on the rear wheel side power transmission path of a real-time four-wheel drive vehicle. In the four-wheel drive vehicle, the front wheel side is always driven and the rear wheel side is driven when necessary. The transaxle 22 mounted on one side of the engine 21 is equipped with a transmission and a transfer.
Outputs power from the axle shaft 23 to the front wheels 24
And to output to the first propeller shaft 25. The first propeller shaft 25 is the driving force transmission device 1
Is connected to the second propeller shaft 26 via 0,
When torque can be transmitted between the shafts 25 and 26, power is output to the axle shaft 28 via the rear differential 27, and the rear wheels 29 are driven.

The driving force transmission device 10 is provided with an outer casing 11 and an end cover 15 which are outer rotating members, and a pressing force generating means 10a and a friction clutch 10b in an annular working chamber which is composed of an inner shaft 12 which is an inner rotating member. There is. The outer case 11 is provided with an inward flange portion 11b at one end of a tubular portion 11a having a predetermined length, and an end cover 15 is screwed into the other end opening of the tubular portion 11a. The inner shaft 12 is provided with an outward flange portion 12b on the outer periphery of the intermediate portion of a stepped cylindrical portion 12a of a predetermined length, and a friction clutch 10b is attached to the outer spline portion extending in the axial direction on the outer periphery of the flange portion 12b. ..

In such an inner shaft 12, the second propeller shaft 26 is fixed by spline-fitting to an axially extending inner spline portion provided on the inner circumference of one end side of the tubular portion 12a, and the tubular portion 12a is fixed. One end is liquid-tightly and rotatably fitted and supported in the inner hole of the inward flange portion 11b of the outer case 11 and the other end is rotatably fitted in the inner hole of the end cover 15. In the outer case 11, the rear end of the first propeller shaft 25 is fixed.

The pressing force generating means 10a is a working piston 13
And the rotor 14, and the friction clutch 10b is of a wet multi-plate clutch type.
6a and clutch disc 16b. Each clutch plate 16a is fitted with a spline portion on the outer periphery thereof to a spline portion 11c provided on the inner periphery of the outer case 11 so as to be integrally rotatable with the case 11 and movable in the axial direction. Each clutch disc 16b has its inner peripheral spline portion fitted to the outer spline portion 12c of the inner shaft 12 so that each clutch plate 16a.
It is located between them and is attached to the shaft 12 so as to be integrally rotatable and movable in the axial direction. A predetermined amount of clutch oil and gas is sealed in the storage chambers of the clutch plate 16a and the clutch disc 16b.

The actuating piston 13 constituting the pressing force generating means 10a is liquid-tightly integrally rotatable with the inner periphery of the other end side of the cylindrical portion 11a of the outer case 11 and slidable in the axial direction. On the other hand, they are mounted on the outer periphery thereof in a liquid-tight manner such that they can rotate in a liquid-tight manner and can slide in the axial direction. The rotor 14 is configured as shown in FIGS. 1 to 3, and a detailed description of the rotor 14 will be given later.
The shaft 12 is assembled so as to be integrally rotatable. The rotor 14 is formed to have substantially the same thickness as the depth of the annular recess 13a provided on one side of the working piston 13, and is fitted in the annular recess 13a.

The end cover 15 is fitted to the outer periphery of the other end of the cylindrical portion 12a of the inner shaft 12 in a liquid-tight manner so as to be slidable in the axial direction and rotatably, and screwed to the outer case 11 so as to be able to move forward and backward. It is liquid-tight. The end cover 15 is axially adjusted in position and fixed to the outer case 11 by caulking means, and one side surface 15a of the end cover 15 contacts an annular outer edge surface of one side of the actuating piston 13, and the one side surface 15a thereof. And the annular recess 13a of the working piston 13 form a fluid chamber in which the rotor 14 is located. A highly viscous fluid such as silicone oil is enclosed in this fluid chamber.

As shown in FIGS. 1 to 3, the rotor 14 has a disk shape, and a large number of recesses 14b are formed on one side surface of the annular main body 14a. The recesses 14b are arranged at equal intervals in the circumferential direction and radially extend in the outer peripheral direction. The recess 14b is composed of a pair of inclined surfaces extending in the circumferential direction from the central portion, and the inclined surfaces are inclined and face each other in the normal and reverse rotation directions. Further, in the rotor 14, two vanes 14c are formed on the other side surface of the annular main body 14a so as to extend from the radial center portion to the radial outer periphery. Each vane 14c has a predetermined thickness, and the same thickness projects from the other side surface.

The rotor 14 is formed to have a thickness substantially the same as the depth of the annular recess 13a of the working piston 13, and the outer periphery thereof is sized so as to be in sliding contact with the outer peripheral surface of the annular recess 13a. , Is integrally rotatably mounted on the outer periphery of the inner shaft 12 and fitted in the annular recess 13a. In this state, a large number of first fluid chambers R1 corresponding to the recesses 14b are formed between the recesses 14b on one side of the annular body 14a of the rotor 14 and the one side of the annular recess 13a of the working piston 13, Moreover, each vane 14c and the end cover 15 on the other side surface of the annular body 14a.
Two second fluid chambers R2 are formed between the vanes 14c between the one side surface 15a.

In the driving force transmission device 10 having such a structure, torque is transmitted when relative rotation occurs between the first and second propeller shafts 25 and 26. That is, when the two shafts 25 and 26 rotate relative to each other, the outer case 11, the working piston 13 and the end cover 15 which are integrally rotatably assembled to the first propeller shaft 25, and the second propeller shaft 26 are integrated. Inner shaft 12 and rotor 14 rotatably assembled
Relative rotation occurs between and.

Therefore, in the pressing force generating means 10a, the viscous fluids in the first and second fluid chambers R1 and R2 are forced to flow at a speed proportional to the relative rotational speed, and the relative movement sequentially in the circumferential direction. Due to the flow resistance in the fluid chambers R1 and R2, a pressure distribution in which the pressure is gradually increased from the upstream end to the downstream end of each recess 14b and each vane 14c is generated. The pressure increasing portion of this pressure distribution increases in proportion to the differential rotation speed, and presses the working piston 13 in the axial direction. As a result, the working piston 13 is moved to the friction clutch 10b.
Is pressed to frictionally engage each clutch plate 16a with the clutch disc 16b through the clutch oil. As a result, in the friction clutch 10b, torque proportional to the differential rotation speed is transmitted from the outer case 11 to the inner shaft 12, and the vehicle is in the four-wheel drive state. Further, in this four-wheel drive state, differential rotation of the front and rear wheels is allowed, and the occurrence of the tight corner braking phenomenon is prevented.

In the driving force transmission device 10, however, the inclined surfaces forming the recesses 14b on one side surface of the rotor 14 perform a wedge action to cause the first fluid chamber R1 to move.
A fluid pressure is generated therein, and a pressure distribution in which the pressure is gradually increased from the downstream end of each vane 14c to the upstream end of the next vane 14c is generated on the other side surface of the rotor 14,
The fluid pressure resulting from the same pressure distribution is generated in each second fluid chamber R2. The fluid pressure generated in the first fluid chamber R1 has a high responsiveness in the low differential region because the positional displacement between the viscous fluid and the gas is instantaneously performed when the differential rotation direction is reversed, and Since the fluid pressure generated in the second fluid chamber R2 corresponds to the differential rotation speed, it increases in the high differential region. Therefore, the fluid pressure generated in both fluid chambers R1 and R2 complements the torque transmission in the low differential region and the high differential region, and improves the torque transmission characteristic in the entire differential region. Especially, since it has good compatibility with the differential rotation speed in the high differential region,
Escape performance is improved when the vehicle is stuck.

In the driving force transmission device 10, one of the two inclined surfaces forming each recess 14b is changed to another shape so as to have a wedge action only during normal rotation, and / or the vane 14c. If is configured to have the directionality of the forward and reverse of the rotation direction, it is possible to absorb the circulating torque peculiar to four-wheel drive by increasing the transmission torque during forward rotation and decreasing the transmission torque during reverse rotation. In addition, it is possible to prevent vibration and squealing noise associated with the rotational phase difference between the front and rear wheels while the vehicle is traveling, and avoid disturbance during the antilock brake system (ABS) control.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a driving force transmission device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a rotor that constitutes a pressing force generating means in the driving force transmission device.

FIG. 3 is a front view (a) and a rear view (b) of the rotor.
Is.

FIG. 4 is a schematic configuration diagram of a four-wheel drive vehicle that employs the same driving force transmission device.

FIG. 5 is a graph showing a relationship between differential rotation speed and transmission torque in the driving force transmission device.

[Explanation of symbols]

10 ... Driving force transmission device, 10a ... Pressing force generating means, 10
b ... 1st friction clutch, 11 ... Outer case, 12 ... Inner shaft, 13 ... Working piston, 14 ... Rotor, 1
4a ... annular body, 14b ... recess, 14c ... vane, 15
... end cover, 16a ... clutch plate, 16b ...
Clutch disc, 25, 26 ... Propeller shaft, R
1, R2 ... Fluid chamber.

Claims (1)

Claim: What is claimed is: 1. A rotary shaft is disposed between both inner and outer rotary members that are coaxially and relatively rotatable with each other, and is operated by relative rotation of both rotary members to connect the rotary members so that torque can be transmitted. A friction clutch that increases or decreases the frictional engagement force according to the axial pressing force applied,
And a pressing force generation means for generating a pressing force in the axial direction according to the relative rotation of the rotating members and applying the pressing force to the friction clutch, the pressing force generating means being provided between the rotating members. A working piston that is liquid-tightly slidable in the axial direction and integrally rotatably mounted on the outer rotating member and faces one side of the friction clutch; and an axial direction formed between the outer rotating member and the working piston. A fluid chamber in which a viscous fluid is sealed at a predetermined interval, and a rotor that is integrally rotatably assembled to the inner rotating member in the fluid chamber and that generates a fluid pressure in the fluid chamber during rotation. In the driving force transmission device, the rotor is formed in a disk shape, and one side surface of the rotor is provided with a large number of recesses having an inclined surface with respect to at least one rotation direction in the circumferential direction, and a diameter is formed on the other side surface of the rotor. Outside Driving force transmission apparatus is characterized by providing one or more vanes extending.